Autonomous driving system

Abstract

To provide an automatic operation device capable of preventing excavation work efficiency from decreasing even when a controller automatically control excavation motion of a work device.SOLUTION: A controller 70 of an automatic operation device 101 controls excavation motion so as to: set a plurality of target positions arranged in a line with intervals on a target track T of a specific part SP of a work device 3 for excavation motion; determine using motion information on the excavation motion whether or not the specific part SP is able to reach an objective target position P2 selected from the plurality of target points within a specific time for the excavation motion; correct the objective target position P2 to a position deviated from a position on the target track T when determining the specific part SP is not able to reach the objective target position P2 within the specific time; make the specific part SP move toward a corrected target position P2'; and make the specific part SP move toward a next target position P3 next to an excavation direction regarding the objective target position P2 of the plurality of the target positions.SELECTED DRAWING: Figure 8

Description

[Technical Field]

[0001] This disclosure relates to technology for the automated operation of work machinery. [Background technology]

[0002] Work machines such as hydraulic excavators perform tasks such as excavation at the work site. The characteristics of the material to be excavated, such as soil, vary depending on the work site. For example, differences in the soil type of the material to be excavated affect the excavation operation performed by the work machine. In excavation work, the operator intuitively understands the soil type and operates the work machine to suit the site. In recent years, automatic driving systems have become known that allow work machines to perform excavation work without the operator having to operate them. For such automatic driving systems to make the work machine perform excavation operations that are suitable for the soil type of the work site, control that takes the soil type into consideration is necessary.

[0003] Patent Document 1 discloses an excavation plan creation device aimed at appropriately considering the influence of soil type when creating an excavation plan. This excavation plan creation device includes a storage unit that stores multiple plan models that have been machine-learned with different soil type parameters, a soil type estimation unit that estimates the soil type, a topographic information acquisition unit that acquires topographic information, and a plan value calculation unit that selects the plan model based on the soil type estimated by the soil type estimation unit, inputs the topographic information acquired by the topographic information acquisition unit to the selected plan model, and calculates the plan value as the output of the plan model.

[0004] Patent Document 2 discloses a power shovel whose purpose is to detect buried foreign objects before contact with the bucket during automatic excavation. This power shovel performs automatic excavation by determining the excavation depth of the bucket from the measurement value of the angle sensor, comparing the excavation depth with the target depth, and adjusting the flow rate to the cylinder. Next, the power shovel determines the excavation resistance vector from the detected value of the load cell, and predicts the presence of foreign objects by determining whether or not there is an abnormality in the determined vector by referring to a database. If the presence of foreign objects is predicted, the power shovel temporarily stops excavation, then corrects the target depth, and resumes automatic excavation. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2021-188362 [Patent Document 2] Japanese Patent Application Publication No. 05-311692 [Overview of the project] [Problems that the invention aims to solve]

[0006] The soil to be excavated may contain localized areas of hard soil, and may also contain localized hard obstacles such as relatively large rocks in addition to soil and sand. However, the technology described in Patent Document 1 does not take into account such locally present hard soil and obstacles within the soil. Therefore, with the technology described in Patent Document 1, it is expected that if the bucket hits hard soil or an obstacle during excavation, the excavation operation will become significantly slower or even stop. In this case, the time required for one cycle from the start to the end of the excavation operation will increase, and the efficiency of the excavation work will decrease.

[0007] Furthermore, in the technology described in Patent Document 2, as mentioned above, if the presence of foreign matter is detected, the excavation is temporarily stopped, and automatic excavation is resumed after the target depth has been corrected. When the excavation work is temporarily stopped in this way, the efficiency of the excavation work decreases. Also, in the technology described in Patent Document 2, when automatic excavation is temporarily stopped, the bucket is moved upward. That is, the bucket is moved to a shallow position in the soil, and then automatic excavation is resumed. Since the automatic excavation after resumption is performed at a shallow position in the soil, the amount of soil excavated in the excavation work decreases, and as a result, the efficiency of the excavation work decreases.

[0008] This disclosure aims to provide an automated operation device that can suppress a decrease in the efficiency of excavation work even when the controller automatically controls the excavation operation of the work device. [Means for solving the problem]

[0009] Provided is an automatic driving device for automatically driving a work machine comprising a machine body and a work device supported by the machine body, comprising a controller for controlling the excavation operation of the work device, wherein the controller sets a plurality of target positions arranged at intervals on the target trajectory of a specific part of the work device in the excavation operation, determines whether the specific part can reach a target position selected from the plurality of target positions within a predetermined time in the excavation operation using operation information related to the excavation operation, corrects the target position to a position outside the target trajectory if it is determined that the specific part cannot reach the target position within the predetermined time, controls the excavation operation so that the specific part moves toward the corrected target position, and then moves toward the next target position among the plurality of target positions that is adjacent to the target position in the excavation direction.

[0010] In excavation work, if hard areas such as hard soil or hard obstacles exist locally on the target trajectory, situations may arise where the speed of the excavation operation gradually decreases or the excavation operation stops as a specific part approaches the hard area. To suppress such situations, the controller of the automated driving device according to this disclosure uses operation information related to the excavation operation to determine whether a specific part can reach the target position within a predetermined time. If it is determined that the specific part cannot reach the target position within the predetermined time, the controller corrects the target position to a position outside the target trajectory and controls the excavation operation so that the specific part moves toward the corrected target position. As a result, even if the hard area exists locally on the target trajectory toward the target position before correction, the controller can move the specific part toward the corrected target position which is outside the target trajectory. Therefore, it is possible to suppress the excavation operation from slowing down or stopping when the work device (e.g., the bucket of the work device) hits the hard area. This suppresses the time required for one excavation cycle. Furthermore, the controller controls the excavation operation so that a specific part moves toward the corrected target position, and then moves toward the next target position. That is, the next target position is a target position located adjacent to the target position in the excavation direction among multiple target positions, and is a position on the target trajectory, not a position outside the target trajectory. Therefore, even if a hard region exists locally on the target trajectory, the number of target positions that need to be corrected among the multiple target positions set on the target trajectory can be minimized. This prevents the actual amount of soil excavated during the excavation operation (actual soil volume) from being significantly lower than the ideal amount of soil that can be excavated (target soil volume) when the specific part moves along the target trajectory from the start to the end of the excavation operation. In other words, the discrepancy between the target soil volume and the actual soil volume can be reduced. From the above, the automatic operation device according to this disclosure can suppress a decrease in the efficiency of the excavation work even when the controller automatically controls the excavation operation of the work device.

[0011] The controller may determine whether a specific part can reach the target position within a predetermined time after the predetermined time has actually elapsed, or it may make the determination based on the prediction result before the predetermined time has elapsed, as in the following specific example.

[0012] Preferably, the controller uses the operation information to predict the excavation operation of the work device and determines, based on the prediction result, whether the specific part can reach the target position within the predetermined time. In this configuration, the controller can determine, based on the prediction result, whether the specific part can reach the target position within the predetermined time without waiting for the predetermined time to elapse. Therefore, if the hardened area is locally present on the target trajectory toward the target position before correction, the controller can determine, before the predetermined time has elapsed, that the specific part cannot reach the target position within the predetermined time, correct the target position to a position off the target trajectory, and move the specific part toward the corrected target position. Therefore, in this configuration, the correction of the target position can be performed at an earlier stage compared to when the determination of whether the specific part can reach the target position within the predetermined time is made after the predetermined time has actually elapsed. This makes it possible to more effectively suppress the slowing down or stopping of the excavation operation when the work device (e.g., the bucket of the work device) hits the hardened area, and to achieve a smoother excavation operation. In this configuration, the controller may predict the excavation operation of the work device using a model for predicting the excavation operation of the work device and the operation information, and determine whether the specific part can reach the target position within the predetermined time based on the prediction result.

[0013] Preferably, the controller predicts the excavation operation of the work device using the operation information and one of several different models selected from each other for predicting the excavation operation of the work device, and determines whether the specific part can reach the target position within the predetermined time based on the prediction result. In this configuration, similarly to the above, the controller can determine whether the specific part can reach the target position within the predetermined time based on the prediction result before the predetermined time has elapsed, without having to wait for the predetermined time to elapse. Therefore, if the hardened region is locally present on the target trajectory toward the target position before correction, the controller can determine before the predetermined time has elapsed that the specific part cannot reach the target position within the predetermined time, correct the target position to a position off the target trajectory, and move the specific part toward the corrected target position. Therefore, in this configuration, the correction of the target position can be performed at an earlier stage compared to when the determination of whether the specific part can reach the target position within the predetermined time is made after the predetermined time has actually elapsed. This makes it possible to more effectively suppress the slowing down or stopping of the excavation operation when the work device (for example, the bucket of the work device) comes into contact with the hard area, resulting in smoother excavation operation.

[0014] Furthermore, in this configuration, the controller predicts the excavation operation of the work device using one of several models selected from a group of models and motion information. In this case, the model used to predict the excavation operation may be one selected by the controller from a group of models based on information entered by the operator into an input device to specify one of the models. In this case, the operator's preferences can be reflected in the characteristics (trends) related to the prediction of the excavation operation.

[0015] Furthermore, the model used to predict drilling operations may be, for example, one selected by the controller from a group of models based on the operation information. More specifically, the controller may, for example, estimate a model suitable for the operation information from among the group of models and select the estimated model to be used to predict drilling operations. This can improve the accuracy of the prediction results. In this case, each of the group of models may be created using operational data (data related to drilling operations) from drilling operations performed in the past. In this case, each of the group of models may be stored in a database in association with the operation information of drilling operations performed in the past. This allows the controller to compare the operation information of the drilling operation to be predicted with the operation information of past drilling operations stored in the database in association with each of the group of models stored in the database, and select a model associated with the same or similar operation information as the drilling operation to be predicted. In this way, the controller can estimate a model suitable for the operation information of the drilling operation to be predicted based on the comparison results. The operation information of drilling operations performed in the past may include, for example, information on drilling force and information on drilling distance.

[0016] Preferably, the controller compares the prediction result with the actual operation result of the work device, and changes the model used to predict the excavation operation to another model selected from the multiple models, depending on the result of the comparison. Specifically, for example, if the difference between the prediction result and the actual operation result of the work device is greater than a predetermined threshold, the controller may select another model from the multiple models that is more suitable for the operation information, and update the model used to predict the excavation operation to the selected other model. This can further improve the accuracy of the prediction result.

[0017] Each of the plurality of models is an interaction model constructed based on the interaction between the working device and the excavation target in the excavation operation, and the interaction model is preferably defined using the mass element of the interaction and at least one of the spring element and the damper element of the interaction. In this configuration, since each of the plurality of models is the above-described interaction model defined using the mass element and at least one of the spring element and the damper element, the controller can make a prediction that more accurately reflects the characteristics of the interaction between the working device and the excavation target in the excavation operation.

[0018] The operation information preferably includes at least one of information on the excavation force in the excavation operation and information on the excavation distance in the excavation operation. In this configuration, since the operation information used for determining whether a specific part can reach the target position within a predetermined time includes at least one of the information on the excavation force and the information on the excavation distance, the controller can make the determination more accurately.

[0019] The specific part is preferably the tip of the bucket included in the working device. In the excavation work, the tip of the bucket is often arranged at a deeper position in the soil than other parts of the working device and often reaches a hard area such as hard soil or a hard obstacle first. Therefore, by setting the tip of the bucket as the specific part, the controller can make the determination more appropriately.

[0020] The modified target position may be located above the original target position and between the previous target position and the next target position, which is adjacent to the target position in the opposite direction to the excavation direction relative to the original target position. In this configuration, even if a hard region exists on the path through which a specific part moves toward the target position, the modification of the target position upward makes it easier for the specific part to avoid the hard region. Furthermore, the excavation reaction force tends to be smaller when the work device excavates shallow soil compared to when the work device excavates deep soil. Therefore, in this configuration, because the modified target position is located above the original target position, the excavation reaction force when the specific part moves toward the modified target position tends to be smaller. This shortens the time required to move the specific part toward the modified target position. Also, since the modified target position is located between the previous target position and the next target position, the direction in which the specific part moves toward the modified target position is less likely to be away from the next target position. This allows for smoother movement of specific parts towards the corrected target position. Specifically, the corrected target position may be, for example, directly above the original target position.

[0021] The modified target position may be such that the distance from the previous target position to the original target position is equal to the distance from the previous target position to the modified target position. Alternatively, the modified target position may be such that the distance from the specific part to the original target position is equal to the distance from the specific part to the modified target position.

[0022] The modified target position may be a position such that the angle between the line segment connecting the previous target position and the target position before modification and the line segment connecting the previous target position and the modified target position is a predetermined angle. Alternatively, the modified target position may be a position such that the angle between the line segment connecting the position of the specific part and the target position before modification and the line segment connecting the position of the specific part and the modified target position is a predetermined angle. [Effects of the Invention]

[0023] According to this disclosure, an automated operation device is provided that can suppress a decrease in the efficiency of excavation work even when the controller automatically controls the excavation operation of the work device. [Brief explanation of the drawing]

[0024] [Figure 1] This is a side view showing an example of a work machine that is subject to automated operation by an automated driving device according to the embodiment of this disclosure. [Figure 2] This block diagram shows the controller of the aforementioned automatic driving device and its related components. [Figure 3] This diagram shows multiple target positions aligned along the target trajectory of a specific part of the work equipment during excavation. [Figure 4] This figure shows an example of correcting the target position. [Figure 5] This figure shows another example of correcting the target position. [Figure 6] This is a block diagram showing another example of the configuration of the aforementioned automatic driving system. [Figure 7] This figure shows an example of the control flow performed by the aforementioned automatic driving device. [Figure 8] This flowchart shows an example of processing performed by the aforementioned automatic driving device. [Figure 9] This diagram illustrates an interaction model, which is an example of a model for predicting the excavation operation of a work device. [Figure 10]This figure shows an example of a determination based on the prediction results using the aforementioned interaction model, and an example of a correction of the target position based on the determination results. [Figure 11] This figure shows another example of a decision based on the prediction results using the aforementioned interaction model, and a correction of the target position based on the decision results. [Figure 12] This figure shows the simulation results of the control using the aforementioned interaction model. [Figure 13] This figure shows the simulation results of the control using the aforementioned interaction model. [Figure 14] This figure shows the simulation results related to the example. [Figure 15] This figure shows the simulation results related to the example. [Figure 16] This is a table showing the values ​​of various parameters used in the simulation. [Modes for carrying out the invention]

[0025] The embodiments of this disclosure will be described below with reference to the drawings. Note that the following embodiments are merely examples of the embodiments of this disclosure and are not intended to limit the technical scope of this disclosure.

[0026] Figure 1 is a side view showing a work machine 100 that is subject to automated operation by the automated driving device 101 according to an embodiment of this disclosure. The work machine 100 shown in Figure 1 is a hydraulic excavator.

[0027] The work machine 100 comprises a lower traveling body 1, an upper rotating body 2 attached to the lower traveling body 1 so as to be able to rotate relative to the lower traveling body 1 around a vertically extending pivot axis Z, and a work device 3 attached to the upper rotating body 2. The lower traveling body 1 and the upper rotating body 2 are examples of the machine body in this disclosure.

[0028] The work device 3 includes a boom 4 rotatably mounted on the upper slewing body 2, an arm 5 rotatably mounted on the boom 4, and a bucket 6 rotatably mounted on the arm 5. The work machine 100 further includes a boom cylinder 7, which is a hydraulic cylinder for rotating the boom 4, an arm cylinder 8, which is a hydraulic cylinder for rotating the arm 5, a bucket cylinder 9, which is a hydraulic cylinder for rotating the bucket 6, and a slewing motor 11, which is a hydraulic motor for slewing the upper slewing body 2.

[0029] The automatic driving device 101 is a device for automatically driving the work machine 100. The automatic driving device 101 may be attached to the work machine 100, or it may be installed in a location away from the work machine 100 and configured to communicate with the work machine 100 wirelessly or by wire.

[0030] As shown in Figure 2, the automatic operation device 101 includes a controller 70. The controller 70 controls the excavation operation of the work device 3 of the work machine 100.

[0031] The excavation operation is the operation of excavating the target to be excavated. The target to be excavated may be, for example, the soil E at the work site (see Figure 1), or a pile of soil and sand placed at the work site. Soil E is the part below the ground level G. In this embodiment, the target to be excavated is soil E.

[0032] The controller 70 includes a computer comprising a processing unit and memory. The controller 70 includes a target setting unit 71, a drilling force calculation unit 72, a position calculation unit 73, a reach determination unit 74, a target position correction unit 75, and a control command unit 76. Each of the target setting unit 71, drilling force calculation unit 72, position calculation unit 73, reach determination unit 74, target position correction unit 75, and control command unit 76 is realized by executing a control program stored in memory.

[0033] The target setting unit 71 sets a target trajectory T and a plurality of target positions. The plurality of target positions include the target target position P2, the next target position P3, and the previous target position P1. The previous target position P1, the target target position P2, and the next target position P3 are the three target positions in this order from the plurality of target positions.

[0034] Figure 3 shows an example of a target trajectory T and multiple target positions Pa to Ph. The target trajectory T is the target path that the bucket tip SP, which is the tip of the bucket 6 of the work device 3, should follow during the excavation operation. Each of the multiple target positions Pa to Ph is a target point that the bucket tip SP passes through. The multiple target positions Pa to Ph are arranged at intervals along the target trajectory T. In the specific example shown in Figure 3, among the multiple target positions Pa to Ph, target position Pa is the starting position of the excavation operation, and target position Ph is the ending position of the excavation operation. The bucket tip SP is an example of a specific part of the work device.

[0035] The target position P2 is a target position selected from multiple target positions, and is the next target position to which the bucket tip SP should move during the excavation operation. The next target position P3 is one of the multiple target positions, and is located adjacent to the target target position P2 in the excavation direction. The previous target position P1 is one of the multiple target positions, and is located adjacent to the target target position P2 in the opposite direction to the excavation direction. The excavation direction is the direction from the start position of the excavation operation (target position Pa) to the end position of the excavation operation (target position Ph), and is the direction along the target trajectory T. The portion connecting two adjacent target positions in the target trajectory T may be a straight line or a curve.

[0036] The target position P2 is updated sequentially as the bucket tip SP approaches the end position during the excavation operation. Specifically, for example, when the bucket tip SP is at or near the target position Pc, the target position P2 is set to the target position Pd. The controller 70 then controls the excavation operation so that the bucket tip SP moves toward the target position P2 (target position Pd). When the bucket tip SP reaches or near the target position Pd, the controller 70 updates the target position P2 to the target position Pe and controls the excavation operation so that the bucket tip SP moves toward the updated target position P2 (target position Pe).

[0037] Hereafter, the previous target position P1 may be referred to as the first target position P1, the target target position P2 may be referred to as the second target position P2, and the next target position P3 may be referred to as the third target position P3.

[0038] The target setting unit 71 may set the target trajectory T and multiple target positions P based, for example, on target information stored in memory beforehand. Alternatively, the target setting unit 71 may set the target trajectory T and multiple target positions P based on target information input to the controller 70 via a storage medium or communication line (not shown in the figure).

[0039] Furthermore, the target setting unit 71 may set a target trajectory T and a plurality of target positions P based on target information input to the controller 70 from the input device 91 shown in Figure 2. The input device 91 may be configured, for example, to allow an operator to input target information. The input device 91 may be mounted on the work machine 100, or it may be installed in a location away from the work machine 100 and configured to communicate with the work machine 100 wirelessly or by wire. The input device 91 may be provided in the automatic driving device 101, or it may be provided in the work machine 100.

[0040] Furthermore, the target setting unit 71 may set a target trajectory T and a plurality of target positions P based on information about the target identified through teaching. Teaching may, for example, involve an operator (e.g., a skilled worker) operating the work machine 100 and storing in memory the path that the bucket tip SP will take and a plurality of passing points during that process.

[0041] The drilling force calculation unit 72 calculates the drilling force during drilling or the drilling reaction force acting on the work device 3 during drilling. The drilling force calculation unit 72 may, for example, calculate the drilling force or drilling reaction force based on information about the drilling force or drilling reaction force input from the detector 92 to the controller 70. The detector 92 detects information about the drilling force or drilling reaction force.

[0042] The detector 92 may include at least one of the following: a pressure sensor for detecting the pressure of the bucket cylinder 9, a pressure sensor for detecting the pressure of the arm cylinder 8, and a pressure sensor for detecting the pressure of the boom cylinder 7.

[0043] The digging force may be, for example, the digging force at the bucket tip SP (specific part) of the work device 3, or the digging force of the entire bucket 6. The digging reaction force may be, for example, the digging reaction force acting on the bucket tip SP (specific part) of the work device 3, the digging reaction force acting on the entire bucket 6, the digging reaction force acting on the entire work device 3, or the digging reaction force acting on a predetermined part of the work device 3.

[0044] The position calculation unit 73 calculates the position of the bucket tip SP. The position calculation unit 73 may calculate the position of the bucket tip SP based on position information input from the detector 93 to the controller 70, for example. Based on the position information, the position calculation unit 73 can calculate the coordinates of the bucket tip SP. The coordinates of the bucket tip SP may be, for example, coordinates on a two-dimensional plane orthogonal to the ground G, or three-dimensional coordinates. The origin of the coordinates may be the coordinates of the bucket tip SP, the coordinates of a preset position at the work site, the coordinates of a preset part of the work machine 100, the starting position of the excavation operation, or the coordinates of another position. The detector 93 detects the position information.

[0045] The detector 93 may include, for example, a sensor for detecting the posture of the work machine 100. Specifically, the detector 93 may include a sensor for detecting the posture of the boom 4, a sensor for detecting the posture of the arm 5, and a sensor for detecting the posture of the bucket 6. The detector 93 may further include a sensor for detecting the posture of the upper slewing body 2.

[0046] The sensor for detecting the posture of the boom 4 may be a sensor for detecting the angle of the boom 4 relative to the upper slewing body 2 or the angle of the boom 4 relative to the horizontal plane, or it may be a sensor for detecting the extension and retraction state of the boom cylinder 7. The sensor for detecting the posture of the arm 5 may be a sensor for detecting the angle of the arm 5 relative to the boom 4 or the angle of the arm 5 relative to the horizontal plane, or it may be a sensor for detecting the extension and retraction state of the arm cylinder 8. The sensor for detecting the posture of the bucket 6 may be a sensor for detecting the angle of the bucket 6 relative to the arm 5 or the angle of the bucket 6 relative to the horizontal plane, or it may be a sensor for detecting the extension and retraction state of the bucket cylinder 9. The sensor for detecting the posture of the upper slewing body 2 may be a sensor for detecting the posture of the upper slewing body 2 relative to the horizontal plane, or it may be a sensor for detecting the slewing angle of the upper slewing body 2 relative to the lower traveling body 1.

[0047] The arrival determination unit 74 determines, using operation information related to the actual excavation operation, whether the bucket tip SP can reach the second target position P2 (target target position P2), which is the next target position to which the bucket tip SP should move after the first target position P1 (the previous target position P1), within a predetermined time during the excavation operation. The target position correction unit 75 corrects the second target position P2 to a position outside the target trajectory T if it is determined that the bucket tip SP cannot reach the second target position P2 within the predetermined time. The control command unit 76 controls the excavation operation so that the bucket tip SP moves toward the corrected second target position P2' (corrected target target position P2'), and then moves toward the third target position P3 (the next target position P3). In the following, the determination of whether the bucket tip SP can reach the second target position P2 (target target position P2) within a predetermined time may be referred to as the "reachability determination," and the act of adjusting the second target position P2 (target target position P2) to a position outside the target trajectory T may be referred to as the "target position adjustment."

[0048] In excavation work, if a hard region R (see Figure 3), such as hard soil or a hard obstacle, is locally present on the target trajectory T in the soil E, the excavation reaction force acting on the work device 3 increases as the bucket tip SP approaches the hard region R. This can cause the excavation speed to gradually decrease or the excavation operation to stop. To prevent such situations, the reach determination unit 74 of the controller 70 performs the reach determination as described above, the target position correction unit 75 of the controller 70 performs the target position correction as described above, and the control command unit 76 of the controller 70 controls the excavation operation as described above. As a result, even if the hard region R is locally present on the target trajectory T toward the second target position P2 (target target position P2) before correction, the controller 70 can move the bucket tip SP toward the corrected second target position P2' (corrected target target position P2'), which is off the original target trajectory T.

[0049] Therefore, it is possible to suppress the slowing down or stopping of the excavation operation when the bucket 6 hits the hard region R. This suppresses the time required for one excavation cycle. Moreover, the controller 70 controls the excavation operation so that the bucket tip SP moves toward the corrected second target position P2' (corrected target position P2'), and then toward the third target position P3 (the next target position P3). In other words, the third target position P3, which is the target position to be moved toward after the corrected second target position P2', is not a position outside the target trajectory T, but a target position located on the target trajectory T. Therefore, even if a hard region R exists locally on the target trajectory T, the number of target positions that need to be corrected among the multiple target positions set on the target trajectory T can be kept to a minimum. This prevents the amount of soil excavated in the actual excavation operation (actual soil volume) from being significantly lower than the amount of soil that can be excavated in the ideal case where the bucket tip SP moves along the target trajectory T from the start to the end of the excavation operation (target soil volume).

[0050] The specific example shown in Figure 3 illustrates the situation when the bucket tip SP moves from the third target position Pc to the fourth target position Pd among multiple target positions Pa to Ph. In this case, the third target position Pc corresponds to the first target position P1 (the previous target position P1), the fourth target position Pd corresponds to the second target position P2 (the target position P2), and the fifth target position Pe corresponds to the third target position P3 (the next target position P3).

[0051] The aforementioned operation information may include at least one of the following: information regarding the digging force during the digging operation and information regarding the digging distance during the digging operation. The information regarding the digging force may be the digging force at the work device 3 (e.g., the bucket tip SP), or it may be the digging reaction force acting on the work device 3 (e.g., the bucket tip SP). The information regarding the digging distance may be the digging distance during the digging operation. The aforementioned operation information may also include information regarding the position of the bucket tip SP.

[0052] The operation information may include two or more of the following: information regarding digging force, information regarding digging distance, and information regarding the position of the bucket tip SP. The digging force or digging reaction force is calculated by the digging force calculation unit 72. The arrival determination unit 74 can calculate the digging distance based on the information regarding the position of the bucket tip SP calculated by the position calculation unit 73. The digging distance may be, for example, the distance from the starting position of the digging operation (target position Pa) to the bucket tip SP, the distance from the first target position P1 to the bucket tip SP, or the distance from a position between the first target position and the second target position to the bucket tip SP.

[0053] The predetermined time may be set, for example, based on a value stored in memory beforehand. The predetermined time may be set, for example, based on input information (e.g., input value) entered by the operator into the input device 91. The predetermined time may be set, for example, by the controller 70 according to the distance between the first target position P1 and the second target position P2. The predetermined time may be a constant value during the excavation operation. The reference point for starting the measurement of the predetermined time may be, for example, the time when the bucket tip SP passes the first target position P1 or its vicinity, or the time when the bucket tip SP passes a position between the first target position P1 and the second target position P2. The predetermined time may be a time determined by the sampling time Ts and the prediction step Nptrj in the table shown in Figure 16, which will be described later. In the specific example shown in Figure 16, the sampling time Ts is 0.05 seconds and the prediction step Nptrj is 60 steps, so the predetermined time is 3 seconds (predetermined time = 0.05 × 60 = 3).

[0054] Furthermore, the controller 70 may update the predetermined time according to the position of the bucket tip SP. Specifically, for example, the controller 70 may update the predetermined time so that it decreases as the bucket tip SP approaches the second target position P2 (target position P2). In this case, the reference point for starting the measurement of the predetermined time is the time when the predetermined time is updated.

[0055] The arrival determination unit 74 may determine whether the bucket tip SP can reach the second target position P2 (target target position P2) within the predetermined time, either when the predetermined time has actually elapsed, or it may determine whether the arrival is possible based on the prediction result before the predetermined time has elapsed. The arrival determination unit 74 can perform the determination using the operation information, for example, as follows.

[0056] When determining whether or not the bucket tip SP can reach the target after a predetermined time has elapsed, the reach determination unit 74 compares the position of the bucket tip SP calculated by the position calculation unit 73 with the second target position P2 (target target position P2) after the predetermined time has elapsed. If the bucket tip SP has not reached the second target position P2 after the predetermined time has elapsed, the reach determination unit 74 determines that the bucket tip SP cannot reach the second target position P2 within the predetermined time.

[0057] Furthermore, the following are specific examples of cases in which the controller 70 uses the operation information to predict the excavation operation of the work device 3 and makes a determination of whether or not it is possible to reach the target based on the prediction result before the predetermined time has elapsed.

[0058] The arrival determination unit 74 may determine that the bucket tip SP cannot reach the second target position within the predetermined time if the excavation reaction force calculated by the excavation force calculation unit 72 during the excavation operation is equal to or greater than a preset reaction force threshold.

[0059] The arrival determination unit 74 may determine whether or not the destination can be reached based on the excavation reaction force calculated by the excavation force calculation unit 72 during the excavation operation and the predetermined time. Specifically, it is as follows: The larger the excavation reaction force, the longer the time required to reach the second target position P2 (target target position P2). The arrival determination unit 74 stores in advance a relationship formula between the excavation reaction force and the required time. If the required time calculated from the relationship formula with the excavation reaction force exceeds the remaining time of the predetermined time, the arrival determination unit 74 may determine that the bucket tip SP cannot reach the second target position P2 within the predetermined time.

[0060] The arrival determination unit 74 may determine whether or not the bucket tip SP can reach the second target position P2 (target target position P2) based on the excavation distance at that time and the predetermined time. Specifically, it is as follows: The arrival determination unit 74 can use the excavation distance at that time to calculate the remaining distance to the second target position P2 (target target position P2). The larger this remaining distance, the longer the time required to reach the second target position P2. The arrival determination unit 74 stores in advance a relationship formula between the remaining distance and the required time. If the required time calculated from the relationship formula exceeds the remaining time within the predetermined time, the arrival determination unit 74 may determine that the bucket tip SP cannot reach the second target position within the predetermined time.

[0061] Furthermore, the arrival determination unit 74 may predict the excavation operation of the work device 3 using a model for predicting the excavation operation of the work device 3 and the operation information, and determine whether the bucket tip SP can reach the second target position P2 (target position P2) within the predetermined time based on the prediction result. The model is one that has been constructed in advance to predict the excavation operation. The model may also be an interaction model constructed based on the interaction between the work device 3 and the excavation target (soil E) during the excavation operation. The interaction model includes at least one parameter that represents the characteristics of the interaction between the work device 3 (e.g., bucket 6) and the excavation target. The prediction of excavation operation using this model will be described later.

[0062] As described above, the target position correction unit 75 corrects the second target position P2 (target target position P2) to a position outside the target trajectory T if it is determined that the bucket tip SP cannot reach the second target position P2 (target target position P2) within the predetermined time. In the specific example shown in Figure 3, the corrected second target position P2' (corrected target target position P2') is located above the second target position P2 before correction and is located between the first target position P1 and the third target position P3. More specifically, the corrected second target position P2' may be located above the second target position P2 before correction and is located between the position of the bucket tip SP and the third target position P3 at that time.

[0063] Even if a hard region R exists on the path that the bucket tip SP moves towards the second target position P2, correcting the second target position P2 upward makes it easier for the bucket tip SP to avoid the hard region R. Also, the excavation reaction force tends to be smaller when the bucket 6 excavates the shallow part of the soil E compared to when the bucket 6 excavates the deep part of the soil E. Therefore, because the corrected second target position P2' is higher than the original second target position P2, the excavation reaction force when the bucket tip SP moves towards the corrected second target position P2' tends to be smaller. This reduces the time required to move the bucket tip SP to the corrected second target position P2'. In addition, since the corrected second target position P2' is located between the first target position P1 and the third target position P3, the direction in which the bucket tip SP moves towards the corrected second target position P2' is less likely to be away from the third target position P3 (leftward in Figure 3). This makes the movement of the bucket tip SP toward the corrected second target position P2' smoother.

[0064] More specifically, the corrected second target position P2' may be directly above the original second target position P2, as shown in Figure 3. In this case, the corrected second target position P2' may be above the original second target position P2 by the correction distance H shown in Figure 3. The correction distance H may be set, for example, based on a value stored in memory beforehand, or based on input information (e.g., input value) entered by the operator into the input device 91. However, the corrected second target position P2' is not limited to being directly above the original second target position P2, but may be shifted relative to the position directly above in the direction of travel (excavation direction) of the bucket tip SP, or shifted relative to the position directly above in the opposite direction to the direction of travel (excavation direction) of the bucket tip SP.

[0065] Furthermore, the corrected second target position P2' is located above the original second target position P2, and is situated between the first target position P1 and the third target position P3. In addition, it may be located such that the distance from the first target position P1 to the original second target position P2 and the distance from the first target position P1 to the corrected second target position P2' are equal in magnitude. The distance from the first target position P1 to the original second target position P2 is the length of the line segment L connecting the first target position P1 and the original second target position P2, and the distance from the first target position P1 to the corrected second target position P2' is the length of the line segment L' connecting the first target position P1 and the corrected second target position P2'.

[0066] Furthermore, the corrected second target position P2' is located above the original second target position P2, and is situated between the first target position P1 and the third target position P3. In addition, it may be located such that the distance from the bucket tip SP to the original second target position P2 at that time is equal to the distance from the bucket tip SP to the corrected second target position P2' at that time. The distance from the bucket tip SP to the original second target position P2 is the length of the line segment L connecting the bucket tip SP and the original second target position P2, as shown in Figure 3, and the distance from the bucket tip SP to the corrected second target position P2' is the length of the line segment L' connecting the bucket tip SP and the corrected second target position P2'.

[0067] Furthermore, the corrected second target position P2' is located above the original second target position P2, and between the first target position P1 and the third target position P3. In addition, it may be located such that the angle between line segment L and line segment L' is the corrected angle θ (a predetermined angle). The corrected angle θ may be set, for example, based on a value stored in memory beforehand, or based on input information (e.g., an input value) entered by the operator into the input device 91. The corrected angle θ (a predetermined angle) is preferably an acute angle.

[0068] Next, we will explain two cases that differ in terms of the positional relationship between the bucket tip SP and the obstacle R, referring to Figures 4 and 5. Figures 4 and 5 are diagrams showing specific examples of methods for correcting the second target position P2 (target target position P2).

[0069] Figure 4 shows Case 1, in which an obstacle R exists below the bucket tip SP. In Case 1, the direction of travel (excavation direction) of the bucket tip SP moving from the first target position P1 towards the second target position P2 before correction is diagonally downward, and at least a portion of the target trajectory portion TP, which is the part of the target trajectory T from the first target position P1 to the second target position P2 before correction, overlaps with the hard region R. In other words, in Case 1, as the bucket tip SP continues moving diagonally downward, the bucket tip SP will come into contact with the top or vicinity of the obstacle R. This Case 1 often occurs, for example, in the early to middle stages of an excavation operation.

[0070] In Case 1 of Figure 4, it is preferable that the modified second target position P2' is set such that, compared to the case where the bucket tip SP is directed towards the second target position P2 before modification, the bucket tip SP passes through a shallower position in the soil E (closer to the ground G), and the bucket tip SP approaches the third target position P3 as it moves towards the modified second target position P2'.

[0071] In this case 1, the corrected second target position P2' may be a position where the lengths of line segment L and line segment L' are the same, as described above, or it may be a position where the angle between line segment L and line segment L' is the corrected angle θ (a predetermined angle).

[0072] Furthermore, in this Case 1, if the arrival determination unit 74 predicts the excavation operation using the model and operation information described later, the target position correction unit 75 may correct the second target position P2 as follows. That is, if the arrival determination unit 74 predicts that the bucket tip SP will stop at the predicted stop position PR shown in Figure 4, the target position correction unit 75 may correct the second target position P2 according to the positional relationship between the position of the bucket tip SP at the time the prediction was made and the predicted stop position PR. In the specific example shown in Figure 4, the position of the bucket tip SP at the time the prediction was made is the first target position P1, but it may also be a position that has advanced from the first target position P1 toward the second target position P2 before correction. However, the position of the bucket tip SP at the time the prediction was made is a position that has not yet reached the predicted stop position PR.

[0073] As shown in Figure 4, if the arrival determination unit 74 predicts that the bucket tip SP will stop at the predicted stop position PR shown in Figure 4, the target position correction unit 75 may correct the second target position P2 to a position at the same height as the predicted stop position PR, and such that the lengths of line segment L and line segment L' are the same. Alternatively, if the arrival determination unit 74 predicts that the bucket tip SP will stop at the predicted stop position PR shown in Figure 4, the target position correction unit 75 may correct the second target position P2 to a position at the same height as the predicted stop position PR, and such that the angle between line segment L and line segment L' is a correction angle θ (a predetermined angle).

[0074] Figure 5 shows Case 2, in which the bucket tip SP and the side of the obstacle R are facing each other. In Case 2, the direction of travel (excavation direction) of the bucket tip SP moving from the first target position P1 towards the second target position P2 before correction is horizontal or diagonally upward, and at least a portion of the target trajectory portion TP, which is the part of the target trajectory T from the first target position P1 to the second target position P2 before correction, overlaps with the hard region R. In other words, Case 1 is a case in which, as the bucket tip SP moves horizontally or diagonally upward, it comes into contact with the side of the obstacle R if it continues to move in that direction. Case 2 often occurs, for example, in the middle to final stages of excavation.

[0075] In Case 2 of Figure 5, it is preferable that the modified second target position P2' is located above the first target position P1, and that the bucket tip SP approaches the third target position P3 as it moves toward the modified second target position P2'.

[0076] Furthermore, in this case 2, if the arrival determination unit 74 predicts the excavation operation using the model and operation information described later, the target position correction unit 75 may correct the second target position P2 as follows. That is, in this case 2, if the arrival determination unit 74 predicts that the bucket tip SP will stop at the predicted stop position PR shown in Figure 5, the target position correction unit 75 may, similar to case 1, correct the second target position P2 according to the positional relationship between the position of the bucket tip SP at the time the prediction was made and the predicted stop position PR. In the specific example shown in Figure 5, the position of the bucket tip SP at the time the prediction was made is the first target position P1, but it may also be a position that has advanced from the first target position P1 toward the second target position P2 before correction. However, the position of the bucket tip SP at the time the prediction was made is a position that has not yet reached the predicted stop position PR.

[0077] As shown in Figure 5, if the arrival determination unit 74 predicts that the bucket tip SP will stop at the predicted stop position PR shown in Figure 5, the target position correction unit 75 may correct the second target position P2 to a position directly above the predicted stop position PR, such that the lengths of line segment L and line segment L' are the same. Alternatively, if the arrival determination unit 74 predicts that the bucket tip SP will stop at the predicted stop position PR shown in Figure 5, the target position correction unit 75 may correct the second target position P2 to a position directly above the predicted stop position PR, such that the angle between line segment L and line segment L' is a correction angle θ (a predetermined angle).

[0078] The arrival determination unit 74 may determine whether the situation is Case 1 or Case 2 as follows, for example. As described above, Case 1 often occurs in the early to middle stages of the excavation operation, and in this Case 1, the direction of travel of the bucket tip SP moving from the first target position P1 toward the second target position P2 before correction is diagonally downward. Therefore, the arrival determination unit 74 may determine that the situation is Case 1 if the position of the bucket tip SP at the time of predicting the excavation operation is in the first half of the target trajectory T, and that the situation is Case 2 if it is in the latter half of the target trajectory T. The arrival determination unit 74 may also determine that the situation is Case 1 if the operating speed of the bucket tip SP includes a vertically downward component, and that the situation is Case 2 if the operating speed of the bucket tip SP includes a vertically upward component.

[0079] The control command unit 76 controls the excavation operation so that the bucket tip SP moves along the target trajectory T. That is, the control command unit 76 controls the excavation operation so that the bucket tip SP passes through multiple target positions or their vicinity. If the target position is not corrected, the control command unit 76 controls the excavation operation so that the bucket tip SP moves toward the second target position P2 (target target position P2) at that time, and if the target position is corrected, the control command unit 76 controls the excavation operation so that the bucket tip SP moves toward the corrected second target position P2' (corrected target target position P2'). In the specific example shown in Figures 3, 4, and 5, the control command unit 76 controls the excavation operation so that the bucket tip SP moves toward the second target position P2 before correction or the second target position P2' after correction, and then moves toward the third target position P3 (the next target position P3). In other words, if the second target position P2 is not modified, the control command unit 76 controls the excavation operation so that the bucket tip SP moves toward the second target position P2 before modification, and then toward the third target position P3. If the second target position P2 is modified, the control command unit 76 controls the excavation operation so that the bucket tip SP moves toward the modified second target position P2, and then toward the third target position P3.

[0080] The control command unit 76 inputs a control input to the work machine 100 to move the bucket tip SP toward the second target position P2 or P2'. This controls the excavation operation of the work device 3. Specifically, the work machine 100 is equipped with a plurality of flow regulators 94. The work machine side controller of the work machine 100 calculates a control command to be input to at least one of the plurality of flow regulators 94 based on the control input, and inputs the control command to at least one of the flow regulators 94. As a result, the bucket tip SP moves toward the second target position P2 or P2'.

[0081] More specifically, for example, the multiple flow regulators 94 include a boom flow regulator 94 for adjusting the flow rate and direction of hydraulic fluid supply to the boom cylinder 7, an arm flow regulator 94 for adjusting the flow rate and direction of hydraulic fluid supply to the arm cylinder 8, a bucket flow regulator 94 for adjusting the flow rate and direction of hydraulic fluid supply to the bucket cylinder 9, and a slewing flow regulator 94 for adjusting the flow rate and direction of hydraulic fluid supply to the slewing motor 11. Each flow regulator 94 may include, for example, a control valve and an electromagnetic proportional valve for adjusting the pilot pressure supplied to the pilot port of the control valve.

[0082] The work machine-side controller of the work machine 100 inputs a control command to at least one of the solenoid proportional valves of the boom flow regulator 94, the arm flow regulator 94, and the bucket regulator 94, based on the control input received from the control command unit 76, so that the bucket tip SP moves toward the second target position P2 or P2'. The solenoid proportional valve outputs a secondary pressure (pilot pressure) corresponding to the control command, and this pilot pressure is input to the pilot port of the control valve corresponding to the solenoid proportional valve, and the opening degree of the control valve is adjusted according to the pilot pressure. As a result, hydraulic fluid at a flow rate corresponding to the control command is supplied to the corresponding cylinder, and the bucket tip SP moves toward the target position.

[0083] The control input that the control command unit 76 of the controller 70 inputs to the work machine 100 may be, for example, a drilling force command to instruct the work machine 100 on the drilling force at the bucket tip SP. This drilling force command corresponds to the control input u(t) in Figure 6, which will be described later, and is a command (a command to instruct the drilling force vector) to indicate the direction of drilling and the magnitude of the drilling force. The work machine side controller of the work machine 100, which receives this control input (drilling force command), inputs control commands to a plurality of electromagnetic proportional valves so that the bucket tip SP moves in the direction corresponding to the drilling force command and with the magnitude of the drilling force corresponding to the drilling force command, thereby distributing hydraulic fluid to the boom cylinder 7, arm cylinder 8, and bucket cylinder 9.

[0084] The above describes the main features of the automated driving system 101 according to this embodiment. More specific aspects of the automated driving system 101 will be described below.

[0085] Figure 6 is a block diagram showing another example of the configuration of the automatic driving system 101. Figure 7 is a diagram showing an example of the control flow performed by the automatic driving system 101.

[0086] As shown in Figure 6, the automatic driving device 101 further comprises a model generator 102 and a database 103. The controller 70 further comprises a model estimation unit 77.

[0087] The model generator 102 creates a new model using operational data from past excavation work (steps S11 and S12 in Figure 7). The operational data includes data related to excavation operations. This data may include, for example, data related to excavation force or excavation reaction force, or data related to excavation distance. The model created by the model generator 102 may be an interaction model, such as the spring-mass damper model shown in Figure 9 later, or it may be any other model. The model generator 102 creates a model using the operational data and inputs the created model into the database 103. The model generator 102 may also create a dataset that associates the created model with the excavation operation information included in the operational data, and input that dataset into the database 103.

[0088] The database 103 sequentially stores new models input from the model generator 102 (step S13 in Figure 7). Thus, the database 103 stores multiple different models for predicting the excavation operation of the work device 3. When the dataset is input from the model generator 102, the database 103 may store each of the multiple models in association with the operation information of the excavation operation corresponding to that model.

[0089] The interaction model includes a plurality of parameters that represent the characteristics of the interaction between the working device 3 (e.g., bucket 6) and the object to be excavated (e.g., soil E). If the interaction model is a spring-mass damper model as shown in Figure 9, the spring-mass damper model includes a plurality of model parameters (mass m(t), viscosity coefficient c(t), and spring constant k(t)), and these model parameters represent the characteristics of the interaction between the working device 3 (e.g., bucket 6) and the object to be excavated. That is, these model parameters are set to values ​​corresponding to the degree of the interaction. In this case, each of the plurality of models stored in the database 103 may include its own plurality of model parameters. Also, if the database 103 stores a plurality of datasets, each of the plurality of datasets may include its own plurality of model parameters and associated operation information (e.g., excavation reaction force and excavation distance). In addition, each spring-mass damper model may use a plurality of system parameters (a) in equation (4) described later, instead of the plurality of model parameters. ∧ 1(k), a ∧ 2(k), b ∧ It may also include 0(k). These system parameters correspond to the aforementioned multiple model parameters and represent the characteristics of the interaction between the work device 3 (e.g., bucket 6) and the object to be excavated. Therefore, each of the multiple models stored in the database 103 may include multiple model parameters and may also include multiple system parameters.

[0090] The model estimation unit 77 estimates a model suitable for the actual drilling operation information at that time, and selects the estimated model to be used for predicting the drilling operation.

[0091] The model estimation unit 77 may, for example, perform model estimation as follows. The model estimation unit 77 substitutes the actual drilling operation information at that time and the multiple system parameters of each model into equation (4) and calculates y(k) in equation (4). That is, the model estimation unit 77 calculates y(k) for each of the multiple models. The model estimation unit 77 compares the multiple y(k) corresponding to the calculated multiple models with the drilling distance y(t) in the actual drilling operation at that time, estimates that the model with the y(k) closest to the actual drilling distance y(t) among the multiple models is the model suitable for the actual operation information, and may select the estimated model as the model to be used for predicting the drilling operation (steps S14, S15 in Figure 7). In this way, the model estimation unit 77 can select a model suitable for the actual drilling operation information.

[0092] Furthermore, if the database 103 stores multiple datasets, the model estimation unit 77 may perform model estimation as follows, for example. The model estimation unit 77 may compare the operation information of the work device 3 (actual operation information) with multiple datasets stored in the database 103, estimate a model suitable for the actual operation information (current operation information), and select the estimated model as the model to be used for predicting the excavation operation (steps S14 and S15 in Figure 7). Specifically, the model estimation unit 77 may compare the current operation information with multiple datasets stored in the database 103, select a dataset containing the same operation information as the current operation information or operation information closest to the current operation information, estimate that the model included in the selected dataset is a model suitable for the current operation information, and select the estimated model as the model to be used for predicting the excavation operation.

[0093] The arrival determination unit 74 uses one model selected by the model estimation unit 77 from among multiple models and the actual operation information at that time to predict the excavation operation of the work device 3 (predicting the position of the bucket tip SP), and based on the prediction result, determines whether the bucket tip SP can reach the second target position P2 (target target position P2) within the predetermined time (steps S16 and S17 in Figure 7).

[0094] As described above, the interaction model includes a plurality of parameters (a plurality of model parameters or a plurality of system parameters) that represent the characteristics of the interaction between the working device 3 (e.g., bucket 6) and the object to be excavated. These parameters represent the characteristics of the interaction between the working device 3 (e.g., bucket 6) and the object to be excavated and have values ​​corresponding to the degree of the interaction. In other words, the plurality of interaction models include, for example, a model suitable for predicting excavation operation when the soil E is of high hardness, a model suitable for predicting excavation operation when the soil E is of low hardness, and a model suitable for predicting excavation operation when the soil E is of intermediate hardness between high and low hardness.

[0095] Therefore, the arrival determination unit 74 can predict the excavation operation of the work device 3 (specifically, the operation of the bucket tip SP) using multiple parameters of the interaction model selected at that time, the operation information at that time, and a pre-set relational expression. For example, the arrival determination unit 74 can predict the position of the bucket tip SP at a certain time after it has elapsed using multiple parameters, the operation information at that time, and a pre-set relational expression (for example, equations (7) to (9) described later). Therefore, based on the prediction result of the excavation operation as described above, that is, the prediction result of the position of the bucket tip SP, the arrival determination unit 74 can determine whether the bucket tip SP can reach the target position P2 within a predetermined time.

[0096] If it is determined that the bucket tip SP can reach the second target position P2 within the predetermined time (YES in step S17 of Figure 7), that is, if no correction is made to the second target position P2, the control command unit 76 outputs a control input to the work machine 100 so that the bucket tip SP moves toward the second target position P2 before the correction, and the work machine side controller outputs a control command corresponding to the control input to the flow regulator 94 (step S18 of Figure 7). The work machine 100 outputs operation information regarding the actual operation result to the controller 70 (step S20 of Figure 7).

[0097] If it is determined that the bucket tip SP cannot reach the second target position P2 within the predetermined time, and the second target position P2 is corrected (NO in step S17 and step S19 in Figure 7), the control command unit 76 outputs a control input to the work machine 100 so that the bucket tip SP moves toward the corrected second target position P2, and the work machine side controller of the work machine 100 outputs a control command corresponding to the control input to the flow regulator 94 (step S18 in Figure 7). The work machine 100 outputs operation information regarding the actual operation result to the controller 70 (step S20 in Figure 7).

[0098] In this automated driving device 101, the controller 70 can determine whether the bucket tip SP can reach the second target position P2 (target target position P2) within a predetermined time based on the prediction result, without having to wait for a predetermined time to elapse. Therefore, if a hard region R exists locally on the target trajectory T toward the second target position P2 before correction, the controller 70 can determine before the predetermined time has elapsed that the bucket tip SP cannot reach the second target position P2 within the predetermined time, correct the second target position P2 to a position off the target trajectory T, and move the bucket tip SP toward the corrected second target position P2'. Therefore, the correction of the second target position P2 can be performed at an earlier stage compared to when the determination of whether or not it can reach the target is actually made after the predetermined time has elapsed. As a result, it is possible to more effectively suppress the slowing down or stopping of the excavation operation when the bucket 6 of the work device 3 hits the hard region R, and a smoother excavation operation is realized.

[0099] Furthermore, the model estimation unit 77 compares the prediction result with the actual operation result of the work device, and changes the model used to predict the excavation operation to another model selected from the plurality of models according to the result of the comparison. Specifically, for example, if the difference between the prediction result and the actual operation result of the work device 3 is greater than a predetermined threshold, the model estimation unit 77 may select another model more suitable for the operation information from the plurality of models and update the model used to predict the excavation operation to the selected other model. Specifically, for example, if the difference between the position of the bucket tip SP predicted by the arrival determination unit 74 and the actual position of the bucket tip SP is greater than a predetermined threshold, the model estimation unit 77 may update the model used for the next prediction to a more suitable model using the method described above. This can further improve the accuracy of the prediction result.

[0100] Figure 8 is a flowchart showing an example of processing by the controller 70 of the automatic driving device 101. The control flow, including the transmission and reception of signals between the automatic driving device 101 and the work machine 100, will be explained with reference to Figure 8.

[0101] As described above, the target setting unit 71 of the controller 70 sets the target trajectory T and multiple target positions Pa to Ph. The controller 70 selects one of the multiple models stored in the database 103 and sets it as the model to be used to predict the drilling operation. The model at the start of the drilling operation may be selected, for example, based on information about the model entered by the worker into the input device 91, or it may be a pre-set model (default model).

[0102] When the automatic operation of the work machine 100 by the automatic driving device 101 is started, the controller 70 controls the excavation operation of the work device 3 so that the bucket tip SP of the work device 3 passes along or near the target trajectory T. When the bucket tip SP descends from the air and makes contact with the ground G, the detector 92 detects whether or not interaction has started between the work device 3 and the soil E (ground G) to be excavated, and the controller 70 determines that interaction between the work device 3 and the soil E has occurred based on the detection signal input from the detector 92. The controller 70 may set the position of the bucket tip SP where the interaction occurred as the starting position of the excavation operation (target position Pa in Figure 3). The starting position (target position Pa) is represented, for example, by coordinates on a two-dimensional plane perpendicular to the ground G or the horizontal plane.

[0103] First, the controller 70 controls the excavation operation of the work device 3 so that the bucket tip SP moves from the target position Pa toward the target position Pb. In this case, the target position Pa corresponds to the first target position (the previous target position), the target position Pb corresponds to the second target position (the target position), and the target position Pc corresponds to the third target position (the next target position).

[0104] The reach determination unit 74 of the controller 70 predicts the excavation operation using a model for predicting the excavation operation and operation information regarding the actual excavation operation of the work device 3. Specifically, the reach determination unit 74 predicts the position of the bucket tip SP (step S101 in Figure 8), and based on the prediction result, determines whether the bucket tip SP can reach the target position Pb, which is the second target position (target position) to which it should move next within a predetermined time (step S102).

[0105] If it is determined that the bucket tip SP cannot reach the target position Pb (second target position) within a predetermined time (NO in step S102), the target position correction unit 75 corrects the target position Pb as the second target position (step S107). The corrected target position Pb (corrected second target position) is set in the manner described above.

[0106] The control command unit 76 then outputs a control input u(t), which is an operation instruction to the work machine 100, so that the bucket tip SP moves toward the corrected target position Pb (step S103). This control input u(t) may be, for example, a drilling force command to instruct the work machine 100 on the drilling force at the bucket tip SP, as described above. This control input u(t) is input to the work machine 100. The work machine side controller of the work machine 100 inputs a control command to at least one of the electromagnetic proportional valves of the plurality of flow regulators 94 so that the work device 3 performs an operation in accordance with the control input u(t) (step S201). As a result, the bucket tip SP moves toward the corrected target position Pb.

[0107] On the other hand, if it is determined that the bucket tip SP can reach the next target position Pb within a predetermined time (YES in step S102), the target position correction unit 75 does not correct the next target position. Then, the control command unit 76 inputs a control input u(t) to the work machine 100 so that the bucket tip SP moves toward the uncorrected target position Pb (step S103). The work machine side controller of the work machine 100 inputs a control command to at least one of the electromagnetic proportional valves of the plurality of flow regulators 94 so that the work device 3 performs an action in accordance with the control input u(t) (step S201). As a result, the bucket tip SP moves toward the uncorrected target position Pb.

[0108] The work machine side controller of the work machine 100 transmits the actual operation results (actual operation information) related to the excavation operation to the automatic operation device 101 (step S202). The operation results may include information on the excavation force or excavation reaction force detected by the detector 92 and information on the posture of the work machine 100 detected by the detector 93.

[0109] The controller 70 of the automatic driving device 101 receives the operation result transmitted from the work machine 100 (step S104). The arrival determination unit 74 of the controller 70 determines, based on the operation result (operation information), whether or not the bucket tip SP actually reached the target position Pb within a predetermined time (step S105).

[0110] For example, if the bucket tip SP is predicted to actually reach the target position Pb within a predetermined time, but the bucket tip SP does not actually reach the target position Pb within that time (NO in step S105), the model estimation unit 77 compares the actual operation result (actual operation information) with multiple models stored in the database 103, estimates a model suitable for the operation information, and selects the estimated model to be used for predicting the excavation operation. The model estimation unit 77 then sets the selected model to be used for predicting the next excavation operation. In other words, the model estimation unit 77 updates the model (step S106). The controller 70 then repeats the process from step S101 onwards.

[0111] If the bucket tip SP actually reaches the target position Pb within the predetermined time as predicted (YES in step S105), the controller 70 repeats the process from step S101 onwards without updating the model. That is, the controller 70 controls the excavation operation of the work device 3 so that the bucket tip SP moves from the target position Pb toward the target position Pc. In this case, the target position Pb corresponds to the first target position (the previous target position), the target position Pc corresponds to the second target position (the target target position), and the target position Pd corresponds to the third target position (the next target position). Hereafter, in the same manner as above, the controller 70 controls the excavation operation so that the bucket tip SP moves along or near the target trajectory T.

[0112] Next, with reference to Figures 9 to 11, specific examples of control by the controller 70 of the automatic driving device 101 will be described. However, the following examples are merely examples of control by the automatic driving device according to this disclosure. Therefore, the automatic driving device according to this disclosure does not necessarily need to perform complex calculations like those in the following examples, and various control methods as already described may be employed.

[0113] Figure 9 is a diagram illustrating an interaction model 200, which is an example of a model for predicting the excavation operation of the work device 3. The control target for control using this model 200 is set as the interaction between the bucket 6 of the work machine 100 and the excavation target (environment) in order to take into account the characteristics of the excavation target. This interaction model 200 is assumed to be a system in which resistance is generated by mass elements, spring elements, and damper elements when the interaction between the bucket 6 and the environment is observed locally during the operation of the bucket 6.

[0114] As shown in Figure 9, this interaction model 200 is a model constructed assuming that the bucket 6 operates within a two-dimensional plane 201. The two-dimensional plane 201 is a plane along the longitudinal direction of the work device 3 and perpendicular to the ground G. The two-dimensional plane 201 has an xt axis set parallel to the longitudinal direction of the work device 3 and horizontal to the ground G, and a yt axis set perpendicular to the ground G. The origin of the two-dimensional plane 201 may be set, for example, at the position where the interaction between the bucket tip SP and the ground G begins (start position), or it may be set at another position.

[0115] The interaction model 200 is a spring-mass damper model that includes a mass element 211 representing the interaction between the working device 3 and the soil E (environment) to be excavated, a damper element 212, and a spring element 213. The mass element 211 is represented by the mass m(t) of the interaction between the working device 3 and the excavated object. The damper element 212 is represented by the viscosity coefficient c(t). The spring element 213 is represented by the spring constant k(t). The damper element 212 and the spring element 213 are connected in parallel. The mass element 211 is connected in series with a parallel element in which the damper element 212 and the spring element 213 are connected in parallel. The equations of motion for this spring-mass damper model are expressed by the following equations (1) to (3).

[0116]

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[0117] Next, the interaction characteristics between the working machine 100 (e.g., bucket 6) and the environment, which change according to operating conditions and environmental conditions, are represented by changes in the model parameters m(t), k(t), and c(t). The discrete-time system can be represented by the following equation (4).

[0118]

Equation

[0119] The control input u(t) is defined by the following equation (5).

[0120]

Equation

[0121] The evaluation function J of DD-MPC is defined by the following formula:

[0122]

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[0123]

number

[0124]

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[0125] Next, we will explain the procedure for updating the excavation trajectory (target trajectory T).

[0126] The drilling trajectory (target trajectory T) will be updated online by following the procedures outlined in Steps 1 and 2.

[0127] [Step 1] Predicting the position of the bucket tip SP The control output y(t) of the Nptrj step is calculated by DD-MPC. Here, a locally linearized model is used, and the next target position to move to is rt(t)=[rx(t),ry(t)] T Predictions are made up to this point. Furthermore, the movement of the bucket tip SP is determined by the current tip position Xt(t)=[xt(t),yt(t)]. T It is assumed that the bucket moves in a straight line from point A to target position rt(t). The model is one-dimensional, but the predicted position Xp(t)=[xp(t),yp(t)] of the bucket tip SP is two-dimensional. T This is calculated using the control output predicted based on the geometric relationship, as shown in equations (13)-(18).

[0128]

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[0129] [Step 2] Updating the excavation trajectory (target trajectory T) If it is determined in Step 1 that the target position cannot be reached, the controller 70 updates the target position based on the relationship between the current bucket tip SP position and the target position. Here, assuming that excavation will advance by the distance between the current bucket tip SP position and the target position after the update, the updated (corrected) target position is determined. The updated target position is then rtnew(t)=[rxnew(t),rynew(t)] T This will be decided.

[0130] (i) When the target position is below the position of the bucket tip SP As shown in Figure 10, consider the case where the obstacle R is below the bucket tip SP, that is, the case where the obstacle R appears when excavating deeply. This case shown in Figure 10 corresponds to Case 1, which was explained with reference to Figure 4. In this case, it is necessary to reduce the depth of the excavation and proceed in the direction of travel. The target position is updated as follows.

[0131]

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[0132] (ii) When the target position is above the position of the bucket tip SP As shown in Figure 11, consider the case where an obstacle R that obstructs excavation is located to the side of the bucket tip SP, that is, when the bucket is moved toward the ground G during excavation, the obstacle R appears. The case shown in Figure 11 corresponds to Case 2, which was explained with reference to Figure 5. In this case, the obstacle R cannot be avoided unless the bucket 6 is moved above the target position before the correction. At this time, the controller 70 updates the target position as shown in the following equations (21) and (22).

[0133]

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[0134] Although an automated driving system according to the embodiments of this disclosure has been described above, this disclosure is not limited to the embodiments described above and includes, for example, the following modifications.

[0135] (A) Model generator and database In the above embodiment, the autonomous driving device 101 includes a model generator 102 and a database 103, but at least one of the model generator 102 and the database 103 may be provided by a separate device (e.g., a server) from the autonomous driving device 101. In this case, the autonomous driving device 101 may be configured to access the database 103 by wireless or wired communication with the separate device. Furthermore, in the autonomous driving device of this disclosure, at least one of the model generator 102 and the database 103 is optional.

[0136] (B) Regarding the selection of a model The model used to predict the excavation operation may be one selected by the controller 70 from among several models based on information entered by the operator into the input device 91 to specify one of the multiple models. In this case, the operator's preferences can be reflected in the characteristics (trends) related to the prediction of the excavation operation.

[0137] In step S102 of Figure 8, the controller 70 may perform the determination using one model, or it may perform the determination while updating multiple models during the process of step S102.

[0138] Furthermore, the controller 70 may, at each sampling time, select a different model from a group of models that is more suitable for the operation information, and update the model used to predict the drilling operation to the selected alternative model.

[0139] (C) Other examples of the model In the automated driving device according to the above embodiment, each of the multiple models is a spring-mass-damper model, but is not limited to this. Each of the multiple models may include, for example, a model representing the hydraulic circuit of the working machine 100 and a model representing the mechanical elements of the soil E, and the controller may use these models to predict the excavation operation of the working machine.

[0140] (D) Excavation force calculation unit and position calculation unit At least one of the digging force calculation unit 72 and the position calculation unit 73 may be provided in the work machine side controller of the work machine 100. In addition, in the automatic operation device of this disclosure, at least one of the digging force calculation unit 72 and the position calculation unit 73 is optional.

[0141] (E) The controller 70 of the automatic driving device 101 may also include the controller on the work machine side of the work machine 100.

[0142] [Examples] Next, embodiments of the present disclosure will be described. Figures 12 and 13 show the simulation results of control using the interaction model 200 shown in Figure 9. Figures 14 and 15 show the simulation results related to a reference example. Figure 16 is a table showing the values ​​of various parameters used in the simulation.

[0143] [Simulation conditions] To briefly verify the effect of control by the automatic driving device 101 according to the embodiment of this disclosure, the controlled object is defined as a second-order lag system in the following equation (23).

[0144]

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[0145] The verification was performed by considering changes in system parameters a1(t), a2(t), and b0(t) as changes in the characteristics of the interaction between the work machine 100 (hydraulic excavator) and the environment. The two-dimensional motion of excavation is simply represented using this one-dimensional transfer function. In this verification, although the controlled object is one-dimensional, the update of the target position in the excavation motion in a two-dimensional plane is confirmed. Therefore, the output of the one-dimensional controlled object is converted to coordinates on a two-dimensional plane by equations (14)-(18). It is also assumed that the controlled object moves linearly to the target position. The target excavation trajectory (multiple target positions) consists of five points on the two-dimensional plane in Table 1 shown in Figure 16 (bottom row of Table 1). When the bucket tip SP is positioned near the target position, the controller 70 changes (updates) the target position to the following value. The controller 70 is given a target value obtained by converting the target trajectory T into one dimension as shown in equation (24).

[0146]

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[0147] [Simulation Results] To verify the effectiveness of the control provided by the automated driving system according to this embodiment, the control results were compared between a case where the controller 70 is equipped with a reach determination unit 74, a target position correction unit 75, and a model estimation unit 77, and a case where these units are not equipped. The verification conditions were set so that the characteristics change during excavation, as shown in the following equation (25).

[0148]

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[0149] As shown in Figures 14 and 15, if the controller 70 does not have a reach determination unit 74, a target position correction unit 75, and a model estimation unit 77, the movement of the bucket tip SP slows down due to the influence of changes in the interaction characteristics between the work machine 100 (hydraulic excavator) and the environment, and excavation takes a very long time. Therefore, if the excavation trajectory control does not take into account changes in the interaction characteristics between the hydraulic excavator and the environment, it may not be possible to perform the desired excavation operation. Note that in Figure 14, the "Characteristic2" region corresponds to the hard region R, and the "Characteristic1" region is the region of soil that is softer than the hard region R (the same applies to Figure 12).

[0150] On the other hand, as shown in Figures 12 and 13, in the embodiments of this disclosure, the movement of the bucket tip is predicted by DD-MPC, and the target trajectory is updated based on the prediction results, thereby enabling smooth excavation operation even when the interaction characteristics between the work machine 100 (hydraulic excavator) and the environment change. It has been confirmed that by updating the target trajectory T (excavation trajectory) with the automatic driving device 101 according to the embodiments of this disclosure, excavation operation can be performed without stopping midway. [Explanation of symbols]

[0151] 1: Lower running body 2: Upper rotating body 3: Working equipment 4: Boom 5: Arm 6: Bucket 70: Controller 100: Working Machinery 101: Automated driving system 200: Interaction Model 211 :Mass element 212: Damper element 213: Spring element P:Target position P1: First target position (the previous target position) P2: Second target location (target location) P2': Modified second target position (modified target position) P3: Third target location (next target location) SP: Bucket tip T:Target trajectory

Claims

1. An automatic driving device for automatically driving a work machine comprising a machine body and a work device supported by the machine body, The device includes a controller that controls the excavation operation of the work device, The aforementioned controller, In the aforementioned excavation operation, multiple target positions are set, which are spaced apart on the target trajectory of a specific part of the work device. In the excavation operation, it is determined whether the specific part can reach a target position selected from the plurality of target positions within a predetermined time, using the operation information related to the excavation operation. If it is determined that the specified part cannot reach the target position within the predetermined time, the target position is corrected to a position outside the target trajectory. An automated operation device that controls the excavation operation such that the specific part moves toward the corrected target position, and then moves toward the next target position among the plurality of target positions that is adjacent to the target position in the excavation direction.

2. The automatic operation device according to claim 1, wherein the controller predicts the excavation operation of the work device using the operation information and determines whether the specific part can reach the target position within the predetermined time based on the prediction result.

3. The automatic operation device according to claim 1, wherein the controller predicts the excavation operation of the work device using any model selected from a plurality of different models for predicting the excavation operation and the operation information, and determines whether the specific part can reach the target position within the predetermined time based on the prediction result.

4. The automatic operation device according to claim 3, wherein the controller compares the prediction result with the actual operation result of the work device, and changes the model used to predict the excavation operation to another model selected from the plurality of models according to the result of the comparison.

5. The automated driving device according to claim 3, wherein each of the plurality of models is an interaction model constructed based on the interaction between the working device and the object to be excavated in the excavation operation, and the interaction model is defined using a mass element of the interaction and at least one of a spring element of the interaction and a damper element of the interaction.

6. The automatic operation device according to claim 1, wherein the operation information includes at least one of the information relating to the drilling force in the drilling operation and the information relating to the drilling distance in the drilling operation.

7. The automatic operation device according to claim 1, wherein the specified part is the tip of a bucket included in the work device.

8. The automated driving device according to claim 1, wherein the modified target position is located above the original target position and is between the previous target position and the next target position, which is adjacent to the target position in the direction opposite to the excavation direction relative to the original target position.

9. The automatic driving device according to claim 8, wherein the modified target position is a position such that the distance from the previous target position or the position of the specific part to the target position before modification is the same as the distance from the previous target position or the position of the specific part to the modified target position.

10. The automatic driving device according to claim 8, wherein the modified target position is a position such that the angle between the line segment connecting the previous target position or the position of the specific part and the target position before modification and the line segment connecting the previous target position or the position of the specific part and the target position after modification is a predetermined angle.

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